Field of the Invention
The present invention relates to an image pickup apparatus such as a digital camera or a digital video camera, a control method therefor, and a storage medium, and in particular, to improvements in flash band compensation technique.
Description of the Related Art
Some image pickup apparatuses such as a digital camera have a rolling shutter image pickup device which sequentially starts exposure and sequentially reads out signals in each row of pixels. Such image pickup apparatuses have a problem that a flash band that creates different levels of luminance appearing in an image in one frame due to an external flash.
Conventionally, there has been proposed a technique to, for a frame where a flash band was detected, compensate for the flash band to generate an image with no different levels of luminance by using a frame immediately preceding the frame or finding an average of a plurality of frames preceding and succeeding the frame (Japanese Laid-Open Patent Publication (Kokai) No. 2011-66567).
According to Japanese Laid-Open Patent Publication (Kokai) No. 2011-66567 above, however, when flash band compensation is performed during a zooming operation, a compensated image with no different levels of luminance cannot be generated because a size of a subject image in frames that are used for the flash band compensation varies.